Bearing support means for rotor



BEARING SUPPORT MEANS FOR ROTOR Filed June 19, 1964 W/W/am W Mhe/ 0 BY Z, 22 i I T E Y5:

| I 1 I I INVENTOR.

United States Patent 3,329,357 BEARING SUPPORT MEANS FOR ROTOR William W. Miner, Cranbury, NJ. 08512 Filed June 19, 1964, Ser. No. 376,339 1 Claim. (Cl. 241-285) This invention relates to reduction mills of the type having a vertical rotor carrying radially disposed hammers or blades and operable to pulverize and decorticate and reduce various materials.

A problem long existent in conventional reduction mills of the type here involved has been that of contamination of the rotor bearings by the liquids released during the grinding or reduction of materials, for example, materials of high liquid content as bagasse, green forages, and sewage, and of grit and other foreign matter. The liquids are of the type which interfere with smooth operation because of their stickiness and gumminess, and also they can contribute materially to corrosion and eventual breakdown of the bearings, particularly when combined with solid particles. Naturally stufling boxes or seals have been provided, particularly at the lower end of such mills but these, even if originally effective, wear away and require replacement.

One of the principal objects of the present invention is to provide an internal arrangement for vertical reduction mills which reduces greatly, if not eliminates entirely, the problem of leakage of liquids and other foreign matter from the mill casing into contact with the bearings and other parts which should be shielded therefrom.

Another object of the invention is to provide a reduc tion mill of the character described in which the rotor can easily be removed for repair or replacement, yet which has a remarkably stable axis of rotation when in operation. The feature of the invention in this respect resides in the provision of a bearing arrangement in which the internal components of the bearing are protected against intrusion of liquids, yet which still can be lubricated as desired without requiring disassembly of the unit, and in fact while it is in operation.

Other objects of the invention, together with the features of novelty appurtenant thereto will appear in the course of the following description.

In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith and in which like reference numerals indicate like parts in the various views:

FIG. 1 is a side elevational view of a reduction mill embodying the invention, parts being broken away and shown in section for purposes of illustration; and

FIG. 2 is an enlarged fragmentary and partly sectional view of the upper end of the rotor drive shaft and rotor and illustrating the rotor in a partially pulled position relative to the drive shaft.

Referring now to the drawing and initially to FIG. 1, reference numeral indicates the hollow cylindrical casing of a typical reduction mill embodying the invention. The top of the casing is partially closed by a top plate 11, which is detachably connected with the casing by means of the bolts 12 spaced around the rim of the top cover plate. These bolts extend through appropriate apertures in the top plate and through the horizontally projecting legs of the angle sections 14 welded or otherwise securely aflixed to the outside of the casing. The top plate is provided with a central opening (not seen) ringed by the filler neck 15 through which material can be introduced as desired to the interior of the casing.

As is conventional, the side of the casing may be provided with access opening 16, which is normally closed by the removable access door 17. A discharge opening 18 is located near the bottom of the casing and it will be understood that it may be connected with any suitable duct means for conducting the pulverized or ground mate rials away from the casing.

The bottom of the casing is closed by the horizontal bottom plate 19, which in this case is carried on a base structure 20. The base is preferably of hollow rectangular constructtion and has the opening 20a in the near side providing access to the interior thereof. The base extends to one side of the unit to support a motor (not shown) which drives the mill through V-belts 21.

Provided in the center of the bottom plate 19 with respect to the rotor casing 10.is a circular opening into which is fitted the lower end of an upstanding cylindrical tube 22. The tube is secured firmly in place, as by weld seam 23, and is of substantial height relative to the depth of the casing. The joint between the tube and the bottom plate should be liquid tight.

Extending upwardly inside the standing tube 22 is the main rotor drive shaft 24. This shaft is journaled near its lower end in a thrust bearing 25 and is provided below the bearing with a set of sheaves 26 for driven connection with the aforementioned V-belts 21. The bearing 25 has the rim or flange 2511 by means of which it is supported from the underside of an apertured mounting disc 27 which is in turn secured to the underside of bottom plate 19. The connection between the bearing flange and disc is made by a plurality of circumferentially spaced bolts 27 extending through corresponding apertures in the bearing flange and threaded into suitably tapped apertures in the mounting disc.

Located within the standing tube 21 and providing an axial bearing for the shaft 24 is the roller bearing assembly 28. The bearing assembly is received in a counterbore formed in the tube which provides an upwardly facing annular shoulder 29. The lower retainer ring 30 of the bearing assembly has a corresponding shoulder which seats on shoulder 29. The inner and outer races of the hearing are sealed off above and below by the usual seals 31.

The shaft 24 has an inwardly stepped, reduced diameter section 24a corresponding in location with the bearing races, above which is located the upper shaft end portion 24b. It will be observed that the latter extends well above the upper end of the standing tube 22.

Surrounding the upper end portion of the shaft is the rotor mounting ring 32. This ring is keyed to the shaft by the means of the key 33. The ring is slideable axially upwardly on the shaft under circumstances later to be described.

Secured to the upper side of ring 32 by means of bolts 34 is the circular end plate 35. The central portion of end plate 35 overlies the shaft end and it is normally secured to the shaft by the bolts 36. The central portion of plate 33 is also provided with a threaded bore 35a therethrough which for reasons later to be described is adapted to receive an elongate thrust bolt 37.

Mounted to the outside of the ring 32 and depending therebelow around the outside of the tube 22 is the cylindrical torque tube 38. This tube carries a plurality of symmetrically arranged, radially extending rotor arms 39 which in turn support the vertical pins 40 to which the flails or hammers 41 of the mill are pivotally mounted. The external rotor construction, particularly with reference to the types and number of arms and blades,

- plays no part in the instant invention; consequently, no

the bearing assembly 28, it will be observed that formed in the inside wall of the standing tube 22 adjacent to bearing is a vertically elongate cavity 42. The upper retainer ring 43 of the bearing assembly is provided with a radial passageway 44 located to register with and open communication between cavity 42 and the space in which the roller bearings 45 are located. The lower end of cavity 42 registers with another passageway 46, which is formed in the lower retainer ring 30 of the bearing assembly. A conduit 48 is connected with passageway 46 by means of coupling 49. The conduit 48 extends downwardly between the shaft and the inside wall of the standing tube and by means of appropriate passageways is conducted to the outside of the mounting disc 27 Where it connects with a conventional external grease gun fitting 50 accessible from and mounted on the outside of the base 20. A similar conduit and fitting identified respectively at 51 and 52 is provided for the lower thrust bearing 25.

During operation of the mill the materal to be ground or pulverized is fed into the casing through the filler neck 15 and is caught up and progressively ground by the swinging and rotating blades or flails 41. As will be evident, any liquid which is freed by the grinding or pulverizing action will, due to gravity, collect and build up on the bottom plate 19. However, the standing tube 22 prevents any of this liquid or any other foreign matter from entering into the bearings as it provides a dam which holds back liquid to a height which would be reached in practical operation of the unit. The standing tube also serves, in combination with the upper bearing assembly 28, to provide a stable rotational axis for the rotor without requiring a bearing on top of the unit.

Whenever it is desired to remove the rotor, this is accomplished in the following manner. The top plate 11 is first disconnected from the casing by removing the bolts 12.The top plate is then lifted free to expose the inside of the casing. If not already in place, the thrust bolt 37 is threaded into bore 35m in the shaft end cover plate 35. The bolts 36 which hold the end plate to the shaft are removed. Turning of the thrust bolt 37 is continued until the inner end engages the top of the shaft, after which sufficient torque is applied in the same direction as to set up a reactive force between the bolt and shaft end sufficient to progressively displace the rotor upwardly with respect to the shaft as illustrated in FIG. 2. The bolt should be long enough to insure that the rotor will be sufliciently freed with respect to the shaft that it can be lifted therefrom when the thrust bolt is fully inserted into the end plate and can be turned no more. In order to hold the bolt centered it is desirable to provide a conical 4 tip on the bolt which is received in a correspondingly shaped cavity in the center of the upper end of the shaft as illustrated.

The bearing assembly 28 can be lubricated as desired by coupling a conventional grease gun with fitting 50. The port 44 provides a path for the grease from the cavity 42 into the bearing interior. Fitting 52 is used to lubricate the lower bearing assembly 25.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claim.

Since many possible embodiments may be made of the invention Without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

A reduction mill comprising a rotor housing having a centrally apertured bottom Wall, a cylindrical standing tube closing the aperture in the bottom wall and rising therefrom centrally in the interior of said housing to a substantial height, a rotor within the housing, said rotor including a cylindrical torque tube rotatably surrounding said standing tube, the inner wall of said torque tube located closely but rotatably adjacent the outer wall of said standing tube along substantially the full length of said standing tube located within said housing, shaft means extending upwardly within said standing tube from below the bottom wall of said casing, first bearing means located below the bottom wall of said housing and providing rotary bearing support for the said shaft means, second rotary bearing means within the upper end poriton of said standing tube and providing rotary bearing support for the upper end of said shaft means, and means connecting the upper end of said shaft means with said torque tube.

References Cited UNITED STATES PATENTS 1,522,983 1/1925 Strassner 29-259 1,909,560 5/1933 Wintroath 308-36.1 2,763,473 9/1956 Madden 3()83 6.1 2,966,313 12/ 1960 Hughes 241191 ANDREW R. JUHASZ, Primary Examiner. 

